a vehicle starts from rest and has an acceleration of 2 metre per second square how long does it take to gain the speed of 20 metre per second ​

Answer:

In a parallel combination of electrical appliances total electric power will increase

Answer is A it will increase

Answer:

(a) 3.93 m/s

(b) 861.66 m

Explanation:

A = 4.5 m/s  [27° S of W] for 3.0 minutes

B = 3.5 m/s [35° S of E] for 4.1 minutes

Distance A = 4.5 x 3 x 60 = 810  m

Distance B = 3.5 x 4.1 x 60 = 861 m

(a) The average speed is defined as the ratio of the total distance to the total time.

Total distance, d = 810 + 861 = 1671 m

total time, t = 3 + 4.1 = 7.1 minutes = 7.1 x 60 = 426 seconds

The average speed is

[tex]v=\frac{1671}{426}=3.93 m/s[/tex]

(b)

[tex]\overrightarrow{A} = 810(- cos 27 \widehat{i} - sin 27 \widehat{j})=- 721.7 \widehat{i} - 367.7 \widehat{j}\\\\\overrightarrow{B} = 861( cos 35 \widehat{i} - sin 35 \widehat{j})= 705.3 \widehat{i} - 493.8 \widehat{j}\\\\\overrightarrow{C} = (- 721.7 + 705.3) \widehat{i} - (367.7 + 493.8) \widehat{j} \\\\\overrightarrow{C}= - 16.4 \widehat{i} - 861.5 \widehat{j}[/tex]

The magnitude is

[tex]C =\sqrt{16.4^2+861.5^2} = 861.66 m[/tex]

Explanation:

Longitudinal waves are waves in which the vibration of the medium is parallel to the direction the wave travels and displacement of the medium is in the same (or opposite) direction of the wave propagation. Mechanical longitudinal waves are also called compressional or compression waves, because they produce compression and rarefaction when traveling through a medium, and pressure waves, because they produce increases and decreases in pressure. 

Answer:

In transverse waves, particles of the medium vibrate to and from in a direction perpendicular to the direction of energy transport.

Explanation:

hope it will help u

Answer:

The correct option is a) 10 mph, 0 mph.

Explanation:

1. The average speed (S) is a magnitude given by:

[tex] S = \frac{D}{T} [/tex]  

Where:

D: is the total distance = 1 mi

T: is the total time = 6 min

[tex] S = \frac{D}{T} = \frac{1 mi}{6 min}*\frac{60 min}{1 h} = 10 mph [/tex]

Hence, the average speed is 10 mph.

2. The average velocity is a vector:

[tex] V = \frac{\Delta d}{\Delta t} = \frac{d_{f} - d_{i}}{t_{f} - t_{i}} [/tex]

Where:

[tex]d_{f}[/tex]: is the final distance                                    

[tex]d_{i}[/tex]: is the initial distance  

[tex]t_{f}[/tex]: is the final time                

[tex]t_{i}[/tex]: is the initial time

Since Juanita ran one mile around her school track, the final position is the same that the initial position, so the magnitude of the average velocity is zero.                                               

Therefore, the correct option is a) 10 mph, 0 mph.

I hope it helps you!          

Answer:

Explanation:

The equation for work is

W = FΔx

We are looking for work, so that means we have to be able to fill in the Force and the displacement. We have Force, but we don't have displacement. But the thing we need to do first is change the 45 minutes to seconds because the velocity is in m/s, not m/min.

45 minutes is 2700 seconds.

That means that  the displacement is

Δx = (.90)(2700) so

Δx = 2430 m

Now we plug that in to find work, along with the given Force:

W = 40(2430) so

W = 97200 J (and that is not the correct number of sig fig's but I have a feeling you're not too into that in class, because if you were, the 40 N would be expressed as 40.0 or 4.0 × 10¹)

Answer:

i) a₁ = -g (sin θ + μ cos θ), x = v₀² / 2a₁

ii) W = mg L sin  θ ,  iii)     Wₙ = 0

iv)  W = - μ m g  L cos  θ x

Explanation:

With a drawing this exercise would be clearer, I understand that you have a block on a ramp and it is subjected to some force that makes it rise, for example the tension created by a descending block.

The movement is that when the system is released, the tension forces are greater than the friction and the component of the weight and therefore the block rises up the ramp

At some point the tension must become zero, when the hanging block reaches the ground, as the block has a velocity it rises with a negative acceleration to a point and stops where the friction force and the weight component would be in equilibrium along the way. along the plane

i) Let's use Newton's second law

the reference system is with the x axis parallel to the ramp

Axis y

      N - W cos θ = 0

X axis

      T - W sin θ - fr = ma

the friction force is

      fr = μ N

      fr = μ mg cos θ

we substitute

      T - m g sin sin θ - μ mg cos θ = m a

      a = T / m - g (sin θ + μ cos θ)

With this acceleration we can find the height that the block reaches, this implies that at some point the tension becomes zero, possibly when a hanging block reaches the floor.

      T = 0

       a₁ = -g (sin θ + μ cos θ)

       v² = v₀² - 2a1 x

       v = 0       at the highest point

       x = v₀² / 2a₁

ii) the work of the gravitational force is

       W = F .d

       W = mg sin  θ   L

iii) the work of the normal force

the force has 90º with respect to the displacement so cos 90 = 0

         Wₙ = 0

iv) friction force work

friction force always opposes displacement

         W = - fr d

         W = - μ m g cos  θ L

Answer:

Jo

Explanation:

irradiating food doesn't make it radioactive (that's contamination) and beta particles are stopped by aluminium foil or thin metals, so it may not pass through thick packaging (usually gamma is used to irradiate foods as it can pass through the packaging)

Answer:

both answer is option C

Explanation:

tag me brainliest

Answer:

Explanation:

The formula for this is

[tex]F_g=\frac{Gm_1m_2}{r^2}[/tex] where F is the gravitational force, G is the gravitational constant, m1 is the mass of one object and m2 is the mass of the other object. We are looking for r, the distance between the centers of their masses.

Filling in:

[tex]7.5*10^{-8}=\frac{6.67*10^{-11}(90.0)(30.0)}{r^2}[/tex] and moving things around to solve for r:

[tex]r=\sqrt{\frac{6.67*10^{-11}(90.0)(30.0)}{7.5*10^{-8}} }[/tex] Doing all that and rounding to the 3 sig fig's you need gives us a distance of 1.55 m

Answer:

The time of motion is 333.3 s

The angular acceleration is -0.0045 rad/s²

Explanation:

Given;

angular distance of the flywheel, θ = 40 rev

initial angular speed, [tex]\omega_i[/tex] = 1.5 rad/s

When the wheel comes to rest, the final angular speed, [tex]\omega_f[/tex] = 0

The angular acceleration is calculated as follows;

[tex]\omega_f^2 = \omega_i^2 + 2\alpha \theta \\\\0 = (1.5 \ rad/s)^2 + 2\alpha (40 \ rev\times \frac{2\pi \ rad}{1 \ rev} )\\\\0 = 2.25 + 160\pi \alpha\\\\160\pi \alpha = - 2.25\\\\\alpha = -\frac{2.25 }{160\pi} \\\\\alpha = -0.0045 \ rad/s^2[/tex]

The time of motion is calculated as;

[tex]\omega_f = \omega _i + \alpha t\\\\0 = 1.5 + (-0.0045t)\\\\0 = 1.5 - 0.0045t\\\\0.0045t = 1.5\\\\t = \frac{1.5}{0.0045} = 333.3 \ s[/tex]

Answer:

Explanation:

The cell is acting like a shell .

Capacity of a shell is given by the following expression.

C= 4πk ε₀ x ab / (b-a )

k is dielectric constant , b and a are outer and inner radius ε₀ is a constant .

Here a = 2.3 x 10⁻⁶ m

b = 2.3 x 10⁻⁶ + .00375 x 10⁻⁶

= 2.30375 x 10⁻⁶ m

b -a = 3.75 x 10⁻⁹ m .

k = 9

4π ε₀ = 1 / 9 x 10⁹ = .111 x 10⁻⁹

C=  .111 x 10⁻⁹ x 9 x 2.3 x 10⁻⁶ x 2.30375 x 10⁻⁶ / 3.75 x 10⁻⁹

= 1.41 x 10⁻¹² F

= 1.41 pF .

Answer:

you have written the definition so what are you asking

Answer:

Heavier than 2.2 pounds

Explanation:

Explanation:

Hey there!

Given;

Mass of one object (m1) = 250kg

Mass of another object (m2) = 400 kg

Distance (d) = 100 m

Gravitational constant (g) = 6.67*10^-11

Now;

[tex]f = \frac{g.m1.m2}{ {d}^{2} } [/tex]

Keep all values;

[tex]f = \frac{6.67 \times {10}^{ - 11} \times 250 \times 400}{ {(100)}^{2} } [/tex]

Simplify

[tex]f = \frac{6.67 \times {10}^{ - 11} {10}^{5} }{10000} [/tex]

[tex]f = \frac{6.67 \times {10}^{ - 6} }{10000} [/tex]

Therefore, gravitational force is 6.67*10^-10.

Hope it helps!

Answer:

Option (c) is correct.

Explanation:

The apparent change in the frequency of light due to the relative motion between the source and the observer is called Doppler's effect.

When the source is moving towards the observer which is at rest, the apparent frequency increases and if the observer is moving away the frequency of sound decreases.

It occurs for both light and sound.  

So, to explain the blue shift of light in the universe is due to the Doppler's effect of light.

Answer:

1kg = 1000g

67kg therefore would be equal to

67 x 1000 = 67,000g = 6.7 x 10⁴g.

Answer:

Explanation:

Newton's law of gravitation states that every particle of matter attracts any other particle in the universe with a force directly proportional to the product of there masses and inversely proportional to the square of the distance between them.

This law is also called universal law because it is applicable to all masses at all distances irrespective of the medium.

Answer:

displacement

Explanation:

Motion can be defined as a change in the location (position) of a physical object or body with respect to a reference point.

This ultimately implies that, motion would occur as a result of a change in location (position) of an object with respect to a reference point or frame of reference i.e where it was standing before the effect of an external force.

A reference point refers to a location or physical object from which the motion (movement) of another physical object or body can be determined.

Mathematically, the motion of an object is described in terms of acceleration, time, distance, speed, velocity, position, displacement, etc.

Displacement can be defined as the change in the position of a body or an object. It is a vector quantity because it has both magnitude and direction.

This ultimately implies that, the difference between the starting and ending positions of a physical object is generally referred to as displacement

Answer:

Coulomb, unit of electric charge in the metre- kilogram- second- ampere system, the basis of SI system of physics unit. The coulomb is defined as the quantity of electricity transported in one second by a current of one ampere.

Answer:

La rapidez del móvil es 12 kilómetros por hora.

Explanation:

Asumamos que el móvil experimenta un movimiento rectilíneo uniforme, cuya ecuación cinemática es la siguiente:

[tex]v = \frac{x}{t}[/tex] (1)

Where:

[tex]x[/tex] - Distancia recorrida, en kilómetros.

[tex]t[/tex] - Tiempo, en horas.

[tex]v[/tex] - Rapidez, en kilómetros por hora.

Si tenemos que [tex]x = 6000\,m[/tex] y [tex]t = 30\,min[/tex], entonces la rapidez del móvil es:

[tex]v = \frac{6000\,m\times \frac{1}{1000}\,\frac{km}{m}}{30\,min \times \frac{1}{60}\,\frac{h}{min} }[/tex]

[tex]v = 12\,\frac{km}{h}[/tex]

La rapidez del móvil es 12 kilómetros por hora.

Answer:

a. Potential energy is highest at Part A

The kinetic energy is highest at Part C and Part D

b. The potential energy is lowest at Part C and Part D

c. The roller coater has equal amount of potential and kinetic energy at Part B, Part D and part F

2) Yes, the mechanical energy is the same from point A to F according to the first law of thermodynamics

Explanation:

The total mechanical energy is constant where the roller coaster moves by only the initial velocity, and the the force of gravity

Total mechanical energy, M.E. = Kinetic energy, K.E. + Potential energy, P.E.

M.E. = K.E. + P.E. = Constant

Therefore, we have;

a. Potential energy is the energy stored in a body, due to its position or elevation, state or arrangement

The higher the elevation, the higher the potential energy, therefore, the highest amount of potential energy is gained when the roller coaster is at the  highest point in the motion = Part A

From M.E. = K.E. + P.E. = Constant, the highest kinetic energy is given at the point the roller coaster has the lowest potential energy, which corresponds with the lowest points = Part C and Part D

b. Potential energy, which is the energy of body due to its position or state is lowest at the lowest points = Part C and Part D

c. The value of potential energy, P.E. due to elevation, can be found as follows

P.E. = Mas, m × Gravity, g × Height, h

Therefore, the potential energy will be half the maximum value where the height, h = (Maximum height)/2 and given that M.E. = K.E. + P.E., the kinetic energy, will increase by the same amount, and we have;

K.E. = P.E. at the half the maximum height of the track = Part B, Part D and part F

2) The mechanical energy is the input energy, which according to the first law of thermodynamics cannot be created and destroyed an it is therefore, constant and it is the same from point A to F

Answer:

(a) The motion is uniform

(b)  11.11 m/s

Explanation:

(a)

From the table below, the motion of the bus is uniform.

(b)

Speed(s) = Δd/Δt

s = Δd/Δt............. Equation 1

From the table,

Given: Δd = 10 km = 10000 m, Δt = 15 minutes = (15×60) = 900 seconds

Substitute these values into equation 1

s = 10000/900

s = 11.11 m/s

Answer:

0.0366 m

Explanation:

We are given;

Current density; J = 540 A/cm² = 540 × 10⁴ m

Current; I = 0.57 A

Now, formula for current density is;

J = I/A

Where A is area = πr²

Thus;

J = I/(πr²)

r = √(I/(Jπ))

r = √(0.57/(540π))

r = 0.0183 m

Diameter = 2 × radius

Diameter = 2 × 0.0183

Diameter = 0.0366 m

Answer:

 v_f = 24.3 m / s

Explanation:

A) In this exercise there is no friction so energy is conserved.

Starting point. On the roof of the building

         Em₀ = K + U = ½ m v₀² + m g y₀

Final point. On the floor

         Em_f = K = ½ m v_f²

         Emo = Em_g

         ½ m v₀² + m g y₀ = ½ m v_f²

        v_f² = v₀² + 2 g y₀

let's calculate

        v_f = √(10² + 2 9.8 25)

        v_f = 24.3 m / s

"Energy" is the ability to do work.

"Work" is the process of using energy.

Answer: 0.5 m

Explanation:

Given

Mass of the person is [tex]m=50\ kg[/tex]

Trampoline launches the person into the air up to height of [tex]h=2\ m[/tex]

Force experience by springs is [tex]F=1960\ N[/tex]

Here, the work done on displacing the springs is equivalent to the Potential energy acquired by the person i.e.

[tex]\Rightarrow F\cdot x=mgh\quad [\text{x=displacement of the trampoline}]\\\\\text{Insert the values}\\\\\Rightarrow x=\dfrac{50\times 9.8\times 2}{1960}\\\\\Rightarrow x=\dfrac{980}{1960}\\\\\Rightarrow x=0.5\ m[/tex]

Answer:

0.5

Explanation:

Answer:

Explanation:

This is a simple gravitational force problem using the equation:

[tex]F_g=\frac{Gm_1m_2}{r^2}[/tex] where F is the gravitational force, G is the universal gravitational constant, the m's are the masses of the2 objects, and r is the distance between the centers of the masses. I am going to state G to 3 sig fig's so that is the number of sig fig's we will have in our answer. If we are solving for the gravitational force, we can fill in everything else where it goes. Keep in mind that I am NOT rounding until the very end, even when I show some simplification before the final answer.

Filling in:

[tex]F_g=\frac{(6.67*19^{-11})(7.2000*10^{26})(5.0000*10^{23})}{(6.10*10^{11})^2}[/tex] I'm going to do the math on the top and then on the bottom and divide at the end.

[tex]F_g=\frac{2.4012*10^{40}}{3.721*10^{23}}[/tex] and now when I divide I will express my answer to the correct number of sig dig's:

[tex]Fg=[/tex] 6.45 × 10¹⁶ N

Answer:

20 m/ s

Explanation:

change in velocity = 4m/ s

[tex]acceleration = \frac{rate \: of \: change \: of \: velocity}{time} [/tex]

[tex]acc = \frac{4}{2} \\ = 2[/tex]

initial velocity = 0m/ s

[tex]2 = \frac{v - 0}{10} [/tex]

cross multiplying

[tex]20 = v[/tex]

so the velocity after 10s will be 20m/s

Answer:

The time in which the pendulum does a complete revolution is called the period of the pendulum.

Remember that the period of a pendulum is written as:

T = 2*pi*√(L/g)

where:

L = length of the pendulum

pi = 3.14

g = 9.8 m/s^2

Here we know that  L = 14.4m

Then the period of the pendulum will be:

T = 2*3.14*√(14.4m/9.8m/s^2) = 7.61s

So one complete oscillation takes 7.61 seconds.

We know that the pendulum starts moving at 8:00 am

We want to know 12:00 noon, which is four hours after the pendulum starts moving.

So, we want to know how many complete oscillations happen in a timelapse of 4 hours.

Each oscillation takes 7.61 seconds.

The total number of oscillations will be the quotient between the total time (4 hours) and the period.

First we need to write both of these in the same units, we know that 1 hour = 3600 seconds

then:

4 hours = 4*(3600 seconds) = 14,400 s

The total number of oscillations in that time frame is:

N = 14,400s/7.61s = 1,892.25

Rounding to the next whole number, we have:

N = 1,892

The pendulum does 1,892 oscillations between 8:00 am and 12:00 noon.

Answer:

25 kg

Explanation:

Given,

Acceleration ( a ) = 2 m/s^2

Force ( F ) = 50 N

To find : Mass ( m ) = ?

Formula : -

F = ma

m = F / a

= 50 / 2

m = 25 kg

So, the mass of the body is 25 kg.